GMAT Quant: Question of the Day!

Try Picking Numbers with the GMAT practice problem of the day!

Last year the price per share of Stock X increased by k percent and the earnings per share of Stock X increased by m percent, where k is greater than m. By what percent did the ratio of price per share to earnings per share increase, in terms of k and m?

A. k/m
B. (k – m)
C. [100 (k – m)]/ (100 + k)
D. [100 (k – m)]/(100 + m)
E. [100 (k – m)]/ (100 + k + m)


If the original price per share of Stock X = 100
Let’s say k = 20
New price per share = 120

Original earnings per share of Stock X = 100
Let’s say m = 5 (since k > m)
New earnings per share = 105

Old ratio of price/earnings = 100/100 = 1
New ratio of price/earnings = 120/105 = approx 1.14

The percent increase is approx 14%.

Plug in our numbers into the answer choices, and look for the choice that also yields 14%:

A. k/m = 20/5 = 4 too small

B. (k – m) = 20 – 5 = 15 too big

C. 100 (15) / 100 + 20 = 1500 / 120 = 12.5 too small

D. 100 (15) / 100 + 5 = 1500/105 = approx 14. CORRECT!

E. 100 (15) / 100 + 20 + 5 = 1500/125 = 12

The answer is (D).

700+ GMAT: Rock Set Theory

Venn diagrams and matrices getting you down? No clue what “elements” are? Sets on the GMAT have a reputation for being tough, but that’s just because most students are less familiar with them. This GMAT board will fill you in on the basics!

The “Intersection” is an upside-down U symbol, and is the OVERLAP of the sets. That is, the intersection contains all the elements that are in BOTH sets. Notice the Venn diagram is used to show the Intersection.

It makes sense that the symbol for “Union” would be a “U” shape. The Union is always the total combined elements. If an element is in EITHER of the sets, then it’s in the Union.

Sometimes Sets questions will be combined with other concepts, such as percentages. They often will not require fancy Venn diagrams or the ability to use a matrix to solve. Watch this Grockit video to see an example of this. You probably didn’t even know this could be considered a “sets” question! 🙂

Like a Venn diagram, a Sets Table (or matrix) is a great way to systematically organize a lot of information, especially for a Sets word problem. Read through this blog on how to set one up! Notice how the table is set up 3 x 3.

 

Rock Statistics Problems on the GMAT!

Statistically-challenged? GMAT tests only a few stats concepts: mean, median, mode, range, standard deviation, min/max, and weighted averages. You probably have seen some of these already!

This sample video question will introduce you to the concept of “average” or the “arithmetic mean.” This is the most highly-tested Statistics concept on the GMAT. The takeaway formula is Average = sum of terms / # of terms.

This video explains how to find weighted averages, which is different from the arithmetic mean (though frequently confused with it). Find the SUM of the each group first, then add the SUMS for the numerator, and combine the total number of elements for the denominator to find the weighted average.

Check out video explanations for other stats concepts such as median, mode, mean, and standard deviation on this Learnboard!

Learnist: Simplifying Algebraic Expressions on the GMAT

Algebra is fundamental to GMAT Quant. A great way to get started on your GMAT prep is to refresh your skills in simplifying algebraic expressions!

PEMDAS is an acronym for the order of operations, which are the basic rules which govern the simplification of algebra. Notice how division/subtraction is always done in order from left to right.

Addition and multiplication are both “commutative” which means it doesn’t matter the order in which the operation is performed. This means that A + B = B + A, and A x B = B x A.

The Associative Property for addition and multiplication means that the numbers can be re-grouped in parentheses without a different outcome. For example, 2 + (3 + 7) = (2 + 3) + 7. Like the Commutative law, this is ONLY true for addition and multiplication.

The Distributive law allows us to “distribute” a factor among terms being added or subtracted. That is, a(b + c) = ab + ac. This law, along with the commutative and associative laws, will become second-nature to you the more you practice!

Remember this rule: you can ONLY cancel factors. Try to simplify the numerator and the denominator as much as possible if you’re looking for things to cancel.

Notice that algebraic expressions can be made more complicated with exponents, including negative exponents. Remember your exponent rules! When you have the same base in the numerator and the denominator, you can subtract the exponents.

Watch some video walk-throughs of some GMAT algebra problems involving order of operations and algebraic expressions on the GMAT – Simplifying Algebraic Expressions learnboard.

10 Ways to Study for the GMAT in Just 30 Days

It’s possible to get a great GMAT score after only 1 month of study, but it requires hard work and discipline. In the middle of applying for scholarships and filling out MBA applications, you’ll need to devote a good amount of time to your GMAT practice as you’ll be cramming what is typically a 2-3 month process into just one! There are excellent GMAT resources online: from free GMAT practice tests to great Test Prep articles. Follow these GMAT study tips to maximize the free GMAT resources for better scores in just one month!

1. Start with the Official Guide. Learn the format, content, and do a general overview of the GMAT test itself using the OG 12th editions. Make sure to go to MBA.com and

2. Study every day, and don’t procrastinate! You will need to be disciplined about your studies. Work backwards from your test date. Don’t cram on the weekends only! With only one month to study, you’ll need to do at least some GMAT every single day.

3. Use MGMAT SC & Powerscore CR to supplement your materials. After the OG, these are two Verbal books that can take your score to the next level.

4. Join Grockit, and Beat the GMAT. These online GMAT sites are vital to building your comfort level with the computer-based format of the GMAT. Practicing in the test-format will only increase your chances of doing well!

5. Study in short, intensive blocks. GMAT study blocks that are too long will ultimately wear you down. Make sure to rotate your study topics often and abide by it, even if you’d like to squeeze in a few more hours. Staying up all night to complete yet another practice test is not always the best choice.

6. Track down success stories to get inspired. If you have a 600 and are eyeing a 700+ score, there are many people out there who have made that leap. Success leaves footprints. Find out what strategies are commonly used by 750+ students, what study plans they keep, and how they build their content-knowledge. Beat the GMAT is an excellent tool for this!

7. Create an Error Log. Re-take quizzes and practice tests from the very beginning of your GMAT studies. Do you find yourself getting the same questions incorrect? This can be a sign that you haven’t learned the content you think you have. Be honest with yourself about what is “sinking in” and what is not. Use an Error Log to assess. You can find many templates online

8. Review all questions. Use the 40/60 rule. 40% of your time should be spent actually answering questions. At minimum, 60% of your time should be spent reviewing.

9. Take at least 1 GMAT practice test per week. Don’t take your practice tests sitting cross-legged on you bed. Utilize your desk and scratch pad as you would on the actual test. Your body needs to adjust to what it feels like to take a 3+ hour test. Because you only have one month to prepare, you should plan to take 4 practice tests, although 6 would be ideal.

10. Use a strategy for each question type. Not only do you have to choose a strategy that works for you, but you have to implement it every time, practicing enough so that is becomes second-hand. Ballet dancers practice a pirouette millions of times, so that when they perform onstage they don’t have to think about it. You want to do the same thing for GMAT.

GMAT Quant: Question of the Day!

Today let’s work on a sets problem using Venn diagrams!

In 1997, N people graduated from college. If 1/3 of them received a degree in the applied sciences, and, of those, 1/4 graduated from a school in one of six northeastern states, which of the following expressions represents the number of people who graduated from college in 1997 who did not both receive a degree in the applied sciences and graduate from a school in one of six northeastern states?

(A) 11N/12
(B) 7N/12
(C) 5N/12
(D) 6N/7
(E) N/7

This question can be solved using a Venn diagram or a matrix to make sense of the information:

The key to understanding this question lies in the last sentence:

who did not both receive a degree in the applied sciences and graduate from a school in one of six northeastern states?

We have two categories to sum: the people who ONLY received a science degree but NOT from one of the 6 schools, and the people who ONLY went to the 6 schools but did NOT receive a science degree. I made up variables for these categories (x and y).

If N = 12, there are 4 applied science students, 1 of which is both. That means x = 3. If 4 students are applied science, then 12-4 = 8 are from one of the six states but NOT applied science. y = 8.

3 + 8 = 11

So we are looking for an answer choice that gives us 11 when N = 12; the answer is (A).

Tough GMAT: Quant Question of the Day

Today, we’ll take a look at a question from the Official Guide from GMAC dealing with sets! As always, try it on your own, then scroll down for an explanation! 🙂

Of the 200 students at College T majoring in one or more of the sciences, 130 are majoring in chemistry and 150 are majoring in biology. If at least 30 of the students are not majoring in either Chemistry or Biology, then the number of students majoring in both chemistry and biology could be any number from:

A) 20 to 50
B) 40 to 70
C) 50 to 130
D) 110 to 130
E) 110 to 150

The question asks what “x” could be.

150 = B + X

130 = C + X

B + C + X = 170

The MAXIMUM overlap is 130, since the Chemistry circle cannot be GREATER than 130. From there we know the answer must be either (C) or (D).

Plugging in our first two equations:

(150 – X) + (130 – X) + X = 170

150 – X + 130 – X + X = 170

150 – X + 130 = 170

150 – X = 40

– X = 40 – 150

-X = -110

X = 110

The answer is (D).

GMAT Data Sufficiency Problem of the Day!

Check out this mean and consecutive numbers question from GMAT Prep!

What is the average (arithmetic mean) of 11 consecutive integers?

1) the average of the first nine integer equals 7
2) the average of the last nune integer equals 9.

To start, recognize that this is a “value” DS question, so we need to know the exact average in order to have sufficiency.

Average = sum of terms/ # of terms

Avg = (a + b + c + d + e + f + g + h + i + j + k) / 11

We know the 11 numbers are consecutive, so we need to know at least one of the numbers and its placement to find the set.

STATEMENT 1.

7 = (a + b + c + d + e + f + g + h + i) / 9

63 = a + b + c + d + e + f + g + h + i

What 9 consecutive numbers sum to 63?

Let’s call the middle number x. We can re-write the sequence as:

63 = (x – 4)+(x – 3)+(x – 2)+(x – 1)+(x)+(x + 1)+(x + 2)+(x + 3)+(x + 4)

63 = 9x

7 = x = middle number of the first 9 terms. We can find the other numbers now since we know they are consecutive integers.

The set is 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13

SUFF.

STATEMENT 2.

The same logic applies. We can determine the set. The answer is (D).

Learnist: How the GMAT Tests “Volume”

Volume is the three-dimensional area — the amount of space enclosed by a shape or object. Remember that you need three different values to find volume and surface area (the length, the width and the height) on the GMAT.

Think of any box — a “rectangular solid” is a just a 3-D rectangle. Find the volume by calculating the length x width x height. Find the surface area by calculating 2lw + 2lh + 2wh.

Like the rectangular solid, to find the volume of a cylinder you will calculate the area of the base and multiply it by the height. For a cylinder, the area of the base will always be equal to the area of a circle: pi x r^2. Just multiply it by “h” to find the volume!

Try a couple practice questions on this GMAT – Volume learnboard!

Learnist: How to Conquer Pacing on the GMAT

Struggling to finish your GMAT practice tests? Not sure how much time to spend on each question? Here’s how conquer the challenge of pacing yourself on the GMAT’s 4 sections: AWA, IR, Verbal, and Quant.

Remember, there are two optional breaks on the GMAT (in between the IR and Quant sections, and in between the GMAT Quant and Verbal sections). Take them! Get up, stretch, and give yourself a mental rest!

As this post from Magoosh wisely warns, however, don’t go over the 8 minutes! The test will resume even if you’re not back in your chair! So by all means take a walk in the hallway outside the testing room, but only for about 5 minutes!

Clueless about where all that time’s going? Keep a single-problem time-log!

This MGMAT blog offers some above-average ideas for how to conquer GMAT pacing, but my favorite is the paragraphs describing the purpose of a “single-problem time-log.”

The goal of the single-problem time-log is so you can get a feel for where you’re losing those extra seconds. The “time position” column lets you know how you’re faring on average compared to idealized pacing per question for that specific question-type.

Check out more tips for How to Conquer Pacing on the GMAT on Learnist!